Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page R1
Report
by the
COMMITTEE ON MDTOR VEHICLE EMISSIONS
Division of Engineering, National Research Council
in accordance with Section 202(c) of the
Clean Air Ameodmcuts of 1970 and
in partial fulfillment of Contract No. 68-01-0402
between
THE ENVIRONMENTAL PROTECTION AGENCY
THE NATIONAL ACADEMY OF SCIENCES
National Academy of Sciences
Washington, D. C.
February 12, 1973
OCR for page R2
NOTTCE
The study reported herein was undertaken under the aegis of the
National Academy of Sciences and with.the express approval of the Governing
Board of the National Research Council.
Such approval indicated that the
Board considered that the problem is of national significance; that eluci-
dation and/or solution of the problem required scientific and technical
competence and that the resources of the National Research Council were
particularly suitable to the conduct of the project.
The members of the committee were selected for their individual
scholarly and technical competence and judgment with due consideration
for the balance and breadth of disciplines. Responsibility for the detailed
aspects of this report rests with the committee, to whom we express our
sincere appreciat ion .
Reports of our study committees are not submitted for approval
to the Academy membership. The report was reviewed by a panel of Academy
members according to procedures established and monitored by the Academy's
Report Review Committee. Such reviews are intended to determine, inter
alla, whether the major questions and relevant points of view have been
addressed and whether the reported findings, conclusions and recommendations
arose from the available data and information. Distribution of the report
was approved, by the President, only after completion of this review
process.
OCR for page R3
lo
CONTENTS
SUMMARY AND CONCLUSIONS
1. INTRODUCTION
1.1 Past Work of the Committee on Motor Vehicle
Emissions
1.2 Panels of Consultants
Page
1
L
6
7
8
1.2.1 Testing, Inspection, and Maintenance 9
1.2.2 Emission-Control Systems 9
1.2.3 Alternate Power Sources 9
1. 2 .4 Manufacturing and Producibility 10
1.2 .5 Driveability 11
1.2 .6 Catalysts 11
1. 2 . 7 Emission Standards and Atmospheric
Chemistry 12
1.3 Other Means of Obtaining Information
111E STANDARDS, CERTIFICATION AND TESTING
3.
13
15
2.1 Numerical Values of Standards 15
2.2 Procedures for Certification, CVS-CH Test 15
2.3 Production-Line Testing 17
2.4 Compliance after Sale, Warranty 20
POTENTIAL OF SPARK-IGNITION INTERNAL-COM13USTION ENGINES
PASSING EMISSION CERTIFICATION FOR 1975 and 1976
22
3.1 Introduction 22
3.2 Current Status of 1975 Systeus 22
3.3 Engine Emissions for 1976 Systems 25
3.3 .1 Introduction 25
3.3.2 Cold-Start Emission Controls 26
3 .3.3 Carburetors 28
3 .3 .4 Electronic Fuel Inj action 28
3.3.5 Exhaust-Gas Recycle (EGR) 29
3.3.6 Potential for Engine Emission Reduction 30
3.4
3.5
3.6 Feedback Control for Air-Fuel Ratio
3.7 Thermal Reactors
3.S Wankel Engine
Catalysts
Three-Way Catalysts
32
43
44
48
50
OCR for page R4
CONTENT S (Cons inued ~
Page
3.9 Stratified-Charge Engines 52
3. 9.1 Fuel-Injected Stratified-Charge Engines
3.9.2 Carbureted Stratified-Charge Engine
3.10 Effect of Emission-Control Devices on Vehicle
Performance, Driveability, Fuel Economy, and
Safety
3.11 Alternative Fuels
3.11. 1 Liquefied Natural Gas and Liquefied
Petroleum Gas
3.11. 2 Status of Liquefied-Gas Substitutes
for Gasoline
3.11.3 Hydrogen
3.11.4 Alcohols
POTENTIAL OF SPARK-IGNITION INTERNAL-COMBIISTION
ENGINES FOR MEETING STANDARDS IN USE
4.1 Introduction
4.2 Differences between Certification Test and
In-Use Operation
4.3 Maintenance Procedures Required for 1975-76
Systems
4.4 Adequacy of the Service Industry
55
57
62
65
65
66
66
68
69
69
69
71
74
4.4.1 Training 74
4.4.2 Number of Mechanics 75
4.4.3 Equipment 76
4,5 State Action
76
4.5.1 Inspection and Maintenance Systems 76
4.5.2 Diagnostic Tests at Garages 81
4.5.3 Selection of Repair/Adjustment
Standards 81
4.5.4 Timing and Cost of Inspection Facilities 82
4.6 Incorporation of Maintenance Considerations in
Emission-Control System Design
4.7 Seminary
84
85
OCR for page R5
~~£
I-`
I..
CONTENTS (Cons inued ~
5 . MANU;FACTVRING , COSTS, AND PRODUCIBILITY
P. age
87
5.1 Manufacturability of Several Proposed Engine
Systems 87
5.1. 1 The Dual-Catalyst System 87
5 .1.2 Diesel Engine 89
5 . 1.3 Wankel Engine 96
5 . l.4 The Carbureted Three-Valve Stratified-
Charge Engine 97
5.1.5 A Typical Feedback-Controlled System 97
5.2 Manufacturability and Costs of Automotive
Exhaus t Catalys ts
5 .3 Summary of Costs of Various Proposed Systems
5.4 Exercise to Illustrate the Impact of Possible
Use of a Mix of Engines and Control Systems
ALTERNATIVE SYSTEMS FOR LOW-E:MISSION AUTOMOBILES
98
100
102
104
6.1 Diesel Engines 104
6 . 2 Gas Turbines 105
6 . 3 S tilling Engi nes 107
6 .4 Electrically Driven Vehicles 108
6.5 Rankine Engines 110
6.6 Other Engines 112
7. DISCUSSION 113
7.1 Introduce on 113
7.2 Dual -Catalyst System 114
7.3 Alternatives to the Dual-Catalyst Approach 116
7.3.1 Carbureted Three-Valve Stratified-Charge
Engine 1 16
7 .3.2 Diesel Engines 117
7 . 3 . 3 Wankel Engines 117
7.3.4 Catalytic Systems with Feedback Control 118
7 .4 Interim S tandards
7.5 Effects of a Delay in Enforcement on Total
Automobile Emissions
7.6 Implementation of 1975 and 1976 Standards and
Related Matters
118
119
124
OCR for page R6
-
APPENDIXES
A. Co~'ittee on Motor Vehicle Emissions
Page
128
B. Panels of Consultants 130
C. Persons, Groups, and Companies from whom the
Committee Obtained or Sought Information 132
D. Announcements placed in Federal Register
requesting information with respect to
technological feasibility
TABLES
3-1 Emissions Performance of Major Manufacturers 1975
Model Year Development Fleets
140
24
3-2 Engine Emissions at Low Mileage: Mean and Standard
Deviation 3
3-3 Examples of Best Low Mileage Emissions Measurements
with Dual-Catalyst Systems on Experimental 1976
Vehicles
Emissions As Function of Mileage for Durability
Tests on Dual-Catalyst Systems
3-5 Low-Mileage Emissions from Compact and European
Vehicles Equipped with Three-Way Catalyst System
3-6 Effect of EGR on Wankel Bare Engine NOX Emissions
3-7 Best Emissions Results, Thermal Reactor and Wankel
Engine 2750-lb Compact Car
3-S Emissions at Low Mileage, Rotary Engine with
Oxidation Catalyst
3-9 Emissions from Military Jeep with Strati fled-Charge
Engine
35
39
47
51
53
54
56
OCR for page R7
in. ~
TABLES (Continued ~
Low-Mileage Emission Levels for PROCO Conversion
3-11 Low-Mileage Emissions Data from Honda Tests of
CVCC Systems
3-12 Durability Data fray Honda Tests of CVCC System
Chronology of Development of the Dual-Catalyst
Sys ten
Estimates of Sticker Prices for Emissions Hardware
from 1966 Uncontrolled Vehicle to 1976 Dual-
Catalyst System
5-3 Summary of Sticker Prices for Emissions Hardware
from 1966 Uncontrolled Vehicle to 1976 Dual-
Catalyst System
5-4 Total Annual Cost to Customer of Emission Controls
For Various Body and Engine Combinations
FIGURES
Page
58
60
61
88
90
94
101
3.1 Typical Dual-Catalyst System 33
7.1 Emissions of Hydrocarbons by
Automobiles in Urban Areas
7.2 Emissions of Carbon Monoxide
by Automobiles in Urban Areas
7.3 Emissions of Oxides of Nitrogen
by Automobiles in Urban Areas
121
122
123
_>
OCR for page R8
OCR for page R9
-¢ ~
NATIONAL ACADEMY 0F SCIENCES
OFFICE OF THE PRESIDENT
2101 CONSTITUTION AVENUE
WASHINGTON, D. C. 20418
The President of the Senate
The Speaker of the House of Representatives
The Administrator of the Environmental Protection Agency
Sirs:
February 15, 1973
I have the honor to transmit a report summarizing the work
and findings. of our.Committee an Motor Vehicle Emissions in accord
with the provisions of Section 6 of Public Law 91-604, the Clean
Air Amendments of 1970. We.trust.that this report will.b.e of
assistance to the Administrator of the Fnvironmenta1 Protection
Agency in discharging his responsibilities finder that Act and that
it will inform the Congress of the progress which has been made,
to date, toward achieving some of the goals of that Act.
.
.
The report constitutes a description, as of 1 February, of
the "technological feasibility," on the part of the automobile
and related industries, of achieving the automotive emissions
control standards established by. the Act. As the.report reveals,
that Act has stimulated an almost worldwide effort to develop
effective emissions ~ ~ ~~ ~
report is presented at a tome when the pace or developments can
readily overtake categorical conclusions based on the inf ormation
available today; it is, therefore, a review of the current "state-
of-the-art," presented while that state is changing rapidly, and
not a summary of a stabilized situation. It is for that reason,
inter alla, that the report presents an analysis but offers no
recommendations concerning enf orcement, on schedule, of the rele-
vant provisions of the Act.
control systems. Of necessity. however this
_ , ,
The Committee defined "technological feasibility'' to mean
that an emissions control system capable of meeting the standards
set for the three major.pollutants can be developed, designed,
produced in large numbers, and maintained in service, all at
reasonable cost. By these criteria, the Committee's analysis
indicates that achievement of the 1975 standards may be techno-
logically feasible and that achievement of the 1976 standards is
likely but may not be attainable on the established schedule.
However, these seemingly definitive conclusions are offered
with several reservations which are held in varying degrees of
OCR for page R10
2 —
gravity by individual members of the Committee. The nature of
these reservations will be found in the report. They are con-
cerned, variously, with the durability in customer use of catalyst-
dependent control systems, the requirement for a network of inspec-
tion and maintenance stations, the actual likelihood of sufficiently
early development of a dual-catalyst system capable of achieving
the 1976 standards, and the likelihood of manufacture for Model
Year 1976, on a scale commensurate with projected total national
production, of a sufficient number of vehicles actually capable of
meeting the 1976 standards in customer use.
The Committee is seriously concerned that the certification
procedure may not prove to be an adequate indicator of the continu-
ing reliability of catalyst-dependent, emissions control systems
under the more stressful, varied conditions of consumer use.
Data in this regard are not yet available, even for systems
intended to meet the 1975 standards. To assure that vehicle
classes certified for production actually do continue to meet the
prescribed standards, the Committee considers it advisable to
develop a network of inspection and maintenance stations and to
train a corps of mechanics sufficient to that task. Some of the
Committee, however, suggest that no more need be done than to
enforce the recall provision of the Act, when so indicated by
defective behavior of a reasonable sample of vehicles. It should
be noted, however, that whereas that provision is binding upon the
manufacturer, it is not mandatory for the vehicle owner to respond.
In view of the low response to recalls for defects relating to
passenger safety (30 to 507), simple use of the recall provision
under these circumstances would not suffice to meet the goals of
the Act. In this regard also, it should be noted that there is not
available, for such national use, a relatively simple, foolproof,
reliable, diagnostic instrument for assessment of the automotive
emission of the three pollutants with which the Act is concerned.
It may be necessary f or the Environmental Protection Agency to
stimulate the research and development required to make such
instrumentation available on the schedule necessitated by the Act.
The Committee found it unnecessary and inadvisable to recommend
a set of interim standards for 1975 or 1976 model year vehicles.
But, while contemplating its responsibility for such a recommenda-
tion, under the terms of the contract, the Committee became aware
of controversies surrounding many aspects of the problem of stan-
dard setting, e.g., the nature and magnitude of the hazards to
health posed by the pollutants released in automotive emissions,
the relationships among the various pollutants and their ambient
concentrations with respect to their health effects, the relative
contributions of mobile and stationary power sources, etc.
Resolution of these controversies appears imperative to long-term
policy with respect to the protection of air quality. Hence, on
page 127, the Committee urges that Congress and the Environmental
!
OCR for page R11
— 3 —
Protection Agency initiate a comprehensive study of these and
related matters. This Academy would be pleased to be of assistance
in such an effort. That recommendation should not be interpreted
as taking exception to the standards established by the Clean Air
Act of 1970. Most of the Committee believes that only if such an
examination were to reveal compelling evidence and arguments to
the contrary should the effort to achieve the emissions control
standards established by the Act be relaxed; indeed, the Committee
is particularly concerned that continued progress be made with
respect to improvement of air quality in those urban centers where,
patently, automotive emissions have contributed significantly to
the deterioration of the local environment.
A major quandary which the Committee wishes to place before
the Congress and the Environmental Protection Agency (page 5)
arises from awareness of the relatively recent development, largely
in the hands of a Japanese manufacturer, of a dual-carbureted,
stratified charge engine. Although the general principle is not new,
the particular design in question, incorporated into small size
engines, has met the 1975 certification standards and bids fair to
meet the 1976 standards. As compared with the catalyst-dependent
systems now being emphasized by the major manufacturers this system
offers the promise of lower initial purchase costs, greater dura-
bility in service and significantly greater fuel economy. The
Committee is concerned that mass production of what are presently
deemed to be relatively fragile, catalyst-dependent systems, of
unproved reliability In actual service, may engender an episode of
considerable national turmoil. It is further concerned that, once
committed to the manufacture of catalyst-dependent control systems,
rather than switch to some more generally acceptable system such as
a version of the stratified charge engine that now offers great
promise, the relatively ponderous automobile industry will continue
to manufacture catalyst-dependent systems for some years, albeit,
presumably, while also seeking more durable catalysts and mechanisms
to reduce the severe fuel penalty of current catalyst-dependent
systems with their associated mechanical features. The dilemma,
then, is to determine what course of action, by government, would
assure the earliest possible optimal outcome while scrupulously
avoiding dictation, by government, of the technology to be used.
The Committee offers no recommendations in this regard.
Relevant to this situation are the costs, per vehicle, asso-
ciated with the initial purchase, maintenance and operation
(including the effects on fuel consumption) of the various emissions
control systems under consideration. The annualized incremental
costs, viz., the cost per car/year for a standard engine, relative
to a 1970 standard engine, due to the emission control system, for
operation and maintenance of the vehicle with the purchase cost of
the system amortized over the first five years of operation, were
OCR for page R12
i '^ )
found, by the Committee to be as follows: 1973 engine, about $100;
single catalyst system (1975 standards), about $225; dual catalyst
system (1976 standards), about $270; and the dual-carbureted
stratified charge engine, about $70. The high annualized costs of
the catalyst systems reflect the serious associated fuel penalties.
For the nation, these costs represent a concrete example of the
principle that the costs of environmental protection can be met only
if they are internalized. The magnitude of this process derives
from the great numbers involved, viz., about 107 (10 million)
vehicles produced per year and almost 108 (100 million) registered
automobiles. Thus, a one-year production of 107 vehicles equipped
with the presently proposed dual-catalyst system would result in
additional expenditures -- as compared with 1970 automobiles -- of
$2.7 billion per year for each of the first five years of the life
of that model year of cars, assuming constant fuel prices, and about
$2 billion per year thereafter.
In due course, all vehicles will be equipped with emission
controls capable of meeting the 1976 standards. There all (108) cars
equipped with the dual-catalyst system, at current costs this would
result in a national annual total expenditure for emissions control
of the order of $23.5 billion (assuming a mean life of ten years/car
with purchase cost amortized over the first five years, and current
fuel prices).
Such figures are to be taken as no more than an indication of
their orders of magnitude. The increased sticker price would tend
to cause consumers to buy smaller cars of greater fuel economy and
the fuel penalty would tend to reduce mileage. The initial costs
will probably decline as dual-catalyst systems and their manufacture
are improved. On the other hand these gains could be offset by
the foreseeable rise in fuel prices. Unless satisfactory feedback
control and fuel injection systems, for catalyst-dependent systems
with the associated mechanical features, become available, the
total costs will be dominated by the fuel penalty associated with
such systems. These costs, in dollars and in depletion of fuel
reserves, are so great that they should serve as a national incentive
to hasten the development of reliable lower-cost alternatives to
the dual-catalyst system as a solution to the problem of emissions
control.
In contrast, several of the promising alternatives, such as
the carbureted stratified-charge engine, carry with them costs of
the order of those already associated with the 1973 engine, viz.,
an annualized cost for emissions control of about $100/car during
the first five years of service, for an annualized total of perhaps
$7.5 billion for the full fleet of 108 cars.
OCR for page R13
- s -
Costs of these magnitudes suggest, of themselves, the need for
attention to a series of considerations which lie outside the scope
of the present report. Among such questions are: What is the
effect of this enterprise on the GNP? Is it, in effect, a stimulus
to the overall economy or are the funds utilized to defray these
expenditures removed from alternate uses in the economy, em., for
improvement in the health care delivery system? If the answer to
the latter is affirmative in significant measure, is this the wisest
use of such funds for protection of the public health? What effects
would large-scale employment of the most promising emissions control
systems have on the international balance of payments? If emissions
control can only be satisfactorily accomplished by acceptance or'
a large fuel penalty, e.g., the dual-catalyst system or the Wankel
engine with thermal reactor, what judgment should be made under
such circumstances? Should it turn out that noble metal catalysts
are more effective and, seemingly, economic than other catalysts,
how should one weigh this raid on the very limited supply of this
resource in the skin of the planet ?
Whereas pollutant emission is undesirable anywhere, emission
control does not appear, today, to be essential on the basis of
either essentially aesthetic or health considerations in large areas
of the nation. Indeed, overall, natural production of hydrocarbons,
carbon monoxide and perhaps NOx far exceeds that from man-made
sources. In view of the costs to the nation, in dollars and in fuel
consumption, of early implementation of the 1975-76 standards, atten-
tion seems warranted to the possibility of temporarily enforcing
the established emissions standards only in those specific urban
areas where air quality is known to be adversely affected by auto-
motive emissions, reserving national implementation for the day
when there are available reliable, relatively inexpensive emissions
control systems which exact no fuel penalty.
Emissions control is but one aspect of "the problem of the
automobile" in our society. This device has given Americans an
'automobility' unknown in previous human history, enriched the
personal experience of each of us, broadened our horizons and helped
to make the large expanse of American geography into one nation.
But this aspect of our society has begun to be defeated by its very
success.
The automobile has also accelerated depletion of several criti-
cal natural resources, including the petroleum which fuels it.
It has scarred the land and choked the city, contributing seriously
to deterioration of the quality of urban life . In the long run,
the truly effective mechanisms for emission control must include a
significant reduction in the number of cars operated in the city, a
solution dependent upon acceptable, public mass transit systems,
and a substantial reduction in the mean size (weight, volume, and
!
OCR for page R14
—i-% ~
at- i
— 6 —
horsepower) of those automobiles which do function in the city, as
well as , perhaps, redistribution of the pattern of physical relation-
ships among dwelling and working.areas. Patently, these are
relatively long-term goals, achievement of which will require
extensive, meticulous study and planning with subsequent large
public expenditures and careful public intervention into the behav-
ior of the private sector.
For the short term, however, automotive emissions control can
be accomplished by a relatively simpler, technological "quick fix,"
and, perhaps, on the schedule established by the Clean Air Amend-
ments of 1970. The attached report summarizes the status of the
alternatives currently offered as means whereby to achieve the
earliest acceptable technological solution to.this problem.
Respectfully yours,
Ph ip Handler
President
!
OCR for page R15
NATIONAL RESEARCH COUNCIL
NATIONAL ACADEMY OF SCIENCES NATIONAL ACADEMY OF ENGINEERING
SI01 CONS~U=ON AVEN" WASHINGTON, D.C. so4~8
COMMITTEE ON MOTOR VE}lICLE EMISSIONS
OF THE DIVISION OF ENGINEERING
Dr. Philip Handler
President
National Academy of Sciences
2101 Constitution Avenue, N.W
Washington, D . C. 20418
Dear President Handler
February 12, 1973
.
.
I am herewith transmitting for submission by the
Academy to the Congress and to the Environmental Protection
Agency the Report of the Committee on Motor Vehicle Emissions
dated February 12, 1973
Sincerely your
2~:
E. L. Ginzton ~
Chairman J
TELEPHONE: 202 -96 ~ - ~ 62 ~
OCR for page R16
